<template>
  <div class="pagination">
    <button :disabled="pageNo === 1" @click="$emit('getPage', pageNo - 1)">
      上一页
    </button>

    <button
      v-if="startNumAndEndNum.start > 1"
      :class="{ active: pageNo === 1 }"
      @click="$emit('getPage', 1)"
    >
      1
    </button>
    <button v-if="startNumAndEndNum.start > 2">···</button>

    <button
      v-for="(page, index) in pageArr"
      :key="index"
      :class="{ active: pageNo === page }"
      @click="$emit('getPage', page)"
    >
      {{ page }}
    </button>

    <button v-if="startNumAndEndNum.end < totalPage - 1">···</button>
    <button
      v-if="startNumAndEndNum.end < totalPage"
      :class="{ active: pageNo === totalPage }"
      @click="$emit('getPage', totalPage)"
    >
      {{ totalPage }}
    </button>
    <button
      :disabled="pageNo === totalPage"
      @click="$emit('getPage', pageNo + 1)"
    >
      下一页
    </button>

    <button style="margin-left: 30px">共 {{ total }} 条</button>
    <!-- 测试 -->
    <!--     <h1>
      start:{{ startNumAndEndNum.start }}----end:{{
        startNumAndEndNum.end
      }}----pageNo:{{ pageNo }}
    </h1> -->
    <!-- <h1>{{ pageArr }}</h1> -->
  </div>
</template>

<script>
export default {
  name: "Pagination",
  props: ["pageNo", "pageSize", "total", "continues"],
  computed: {
    totalPage() {
      return Math.ceil(this.total / this.pageSize);
    },
    //计算出连续页码的起始数字与结束数字
    startNumAndEndNum() {
      let { totalPage, continues, pageNo } = this;
      let start = 0,
        end = 0;
      if (continues > totalPage) {
        start = 1;
        end = totalPage;
      } else {
        start = pageNo - parseInt(continues / 2);
        end = pageNo + parseInt(continues / 2);
        if (start < 1) {
          start = 1;
          end = continues;
        }
        if (end > totalPage) {
          end = totalPage;
          start = totalPage - continues + 1;
        }
      }
      return { start, end };
    },
    pageArr() {
      let Arr = [];
      for (let i = 0; i <= this.startNumAndEndNum.end; i++) {
        if (Arr.indexOf(i) === -1) {
          Arr.push(i);
        }
      }
      let newArr = Arr.filter((value) => value >= this.startNumAndEndNum.start);
      return newArr;
    },
  },
};
</script>

<style lang="less" scoped>
.pagination {
  text-align: center;
  button {
    margin: 0 5px;
    background-color: #f4f4f5;
    color: #606266;
    outline: none;
    border-radius: 2px;
    padding: 0 4px;
    vertical-align: top;
    display: inline-block;
    font-size: 13px;
    min-width: 35.5px;
    height: 28px;
    line-height: 28px;
    cursor: pointer;
    box-sizing: border-box;
    text-align: center;
    border: 0;

    &[disabled] {
      color: #c0c4cc;
      cursor: not-allowed;
    }

    &.active {
      cursor: pointer;
      background-color: #409eff;
      color: #fff;
    }
  }
}
.active {
  background-color: #409eff;
}
</style>